Battery operated hair dryer

ABSTRACT

A battery operated hair dryer includes a battery management and control module to control how to efficiently dry a user&#39;s hair while maintaining the health and charge of the battery.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/951,786 filed on Apr. 12, 2018, which is based on and claims priorityto U.S. Provisional Patent Application No. 62/584,528 filed on Nov. 10,2017, which is incorporated herein by reference in its entirety for allpurposes.

FIELD OF THE INVENTION

The present invention relates generally to the field of electrichandheld hair dryers, and specifically to a battery operated handheldhair dryer.

BACKGROUND

In general, hair dryers, also called “blow dryers” are well known.Typical handheld hair dryers blow ambient air or heated air over damphair to accelerate the evaporation of water particles, thereby dryingthe hair more quickly than it would dry on its own. Typical hair dryersare powered by electricity from the power grid, that is, they are almostalways plugged into a wall socket to get power. Typical hair dryersinclude two key components: a fan and a heating element downstream fromthe fan that selectively heats air as it is blown past by the fan. Thefirst handheld, household hair dryers were introduced in the first halfof the 20^(th) century, and have only changed slightly in almost 100years.

Hair dryer performance can be measured a number of different ways, butthe most common measurements include air flow rate, velocity of the airas it leaves the hair dryer, and how much the air temperature increasesrelative to the ambient air temperature.

Existing hair dryers include a fan and at least one electric heatingcoil. The electric heating coils generate heat through the process ofresistive heating. Electric current passing through the heating elementis resisted by a coil of wire that results in the generation of heat.Resistance heating elements are typically made of wire or ribbon thatmay be straight, coiled, or formed into any other suitable shape.Resistive heating elements demand large amounts of electric current togenerate heat sufficient to dry hair. As a result, hair dryers that useresistive heating elements have historically not been well suited to bepowered by batteries.

Typical hair dryers also include switches that allow a user to controlbasic functions of the hair dryer. For example, typical hair dryers mayinclude “hi” “low” and “off” settings for heat, and a “hi” and “low”setting for the fan. The aforementioned basic settings are adequate forhair dryers that draw electricity from the power grid, and until nowthere has been little motivation to better optimize performance of thehair dryer from the perspective of maintaining battery charge.

Until now, batteries capable of generating sufficient power(voltage×current) for a sufficient period of time to enable reliablehair drying performance have been prohibitively heavy, large, andexpensive. Meanwhile, existing hair dryers, although lightweight, sufferfrom being tethered to a power outlet. Furthermore, a user drying theirhair must move the hair dryer continuously around their head, and thepower cord is often a nuisance.

As such, there is a need for a battery operated hair dryer that includesa battery management system to allow the hair dryer to efficiently dryhair while maintaining a maximum battery charge in a lightweight,inexpensive package.

SUMMARY

The present invention relates to a battery operated hair dryer. The hairdryer has a housing which contains all of the components of the hairdryer. A battery pack including at least one battery cell is included inthe housing and is electrically connected to a battery management andcontrol module. The hair dryer also includes at least one switch tocontrol the operation of the hair dryer. A heating assembly is disposedwithin the housing and includes a fan attached to an electric motor. Theheating assembly also includes at least one heating element. The motoris driven by electrical current from the battery pack and turns the fan,which draws ambient air into an inlet and expels air through an outlet.The heating element is positioned such that air passing through theheating assembly may be heated to a temperature greater than the ambientair temperature. The battery management and control module iselectrically connected to the heating assembly and adjusts the amount ofcurrent delivered from the battery pack to the fan and the heatingelement so that the drying performance of the hair dryer is optimized,while maintaining the charge and health of the battery pack.

It will be understood by those skilled in the art that one or moreaspects of this invention can meet certain objectives, while one or moreother aspects can lead to certain other objectives. Other objects,features, benefits and advantages of the present invention will beapparent in this summary and descriptions of the disclosed embodiment,and will be readily apparent to those skilled in the art. Such objects,features, benefits and advantages will be apparent from the above astaken in conjunction with the accompanying figures and all reasonableinferences to be drawn therefrom.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of a battery operatedhair dryer in accordance with the invention;

FIG. 2 is side view of the battery operated hair dryer of FIG. 1;

FIG. 3 is an exploded perspective view of the battery operated hairdryer of FIG. 1;

FIG. 4 is a front view of the battery operated hair dryer of FIG. 1;

FIG. 5 is a section view of the battery operated hair dryer of FIG. 1taken generally along the line 5-5 in FIG. 4;

FIG. 6 is a detail view taken generally along the line 6-6 in FIG. 5showing a light ring and outlet grille;

FIG. 7 is a perspective view of one embodiment of a heating assembly inaccordance with the invention;

FIG. 8 is another perspective view of the heating assembly of FIG. 6;

FIG. 9 is an exploded perspective view of the heating assembly of FIG.6;

FIG. 10 is a perspective view of the heating assembly of FIG. 6 with aduct removed so the heating coil is visible;

FIG. 11 is another perspective view of the heating assembly of FIG. 6with the duct removed so the heating coil is visible;

FIG. 12 is a perspective view of one embodiment of a battery pack inaccordance with the invention;

FIG. 13 is another perspective view of the battery pack of FIG. 11;

FIG. 14 is a perspective view of one embodiment of battery cells, abattery management module, and a switch module in accordance with theinvention;

FIG. 15 is a front view of one embodiment of a battery operated hairdryer in accordance with the invention;

FIG. 16 is a side section view of the battery operated hair dryer ofFIG. 15, taken generally along the line 16-16 in FIG. 15;

FIG. 17 is a perspective view of one embodiment of a heating module forthe battery operated hair dryer of FIG. 14; and

FIG. 18 is another perspective view of the heating module of FIG. 15.

DETAILED DESCRIPTION

Referring now to the drawing figures, the invention provides a batteryoperated hair dryer 10. Hair dryer 10 includes a main housing 20 thatencloses all of the components of the hair dryer. FIGS. 1-2 show hairdryer 10 resting in an optional storage cradle 12, that provides supportto the hair dryer when it is not in use, allowing the hair dryer tooccupy a minimal amount of counter space. In some embodiments, storagecradle 12 may also provide power to hair dryer 10 when the hair dryer isstored in the storage cradle.

Hair dryer 10 includes three subsystems enclosed in main housing 20 thatenable the hair dryer to function: (1) a battery pack 16, (2) a batterymanagement and control module 40, and (3) a heating assembly 50. Asshown in the exploded view of FIG. 3, main housing 20 defines anenclosure that encloses all of the components of the hair dryer 10. Ingeneral, battery pack 16 is located in a bottom section 32 of mainhousing 20. In the embodiment shown, part of battery pack 16 is alsolocated in a middle section 42, which also includes control switches 44and a battery indicator 38. Heating assembly 50 is located in a topsection 52 of main housing 20. Heating assembly 50 includes at least oneheating element 54, at least one fan 56, and other components that willbe described in detail below. In the embodiment shown, batterymanagement and control module 40 is disposed substantially between topsection 52 and middle section 42. In the embodiment shown, batterymanagement and control module 40 comprises a printed circuit board thatcreates a physical barrier between the top section 52 and the middlesection 42. Although battery management and control module 40 creates abarrier between top section 52 and middle section 42 in the presentembodiment, other means of separating the top section and the middlesection may alternatively be used without departing from the invention.In some embodiments, it may also be desirable to direct air throughmiddle section 42 and bottom section 32 to improve battery performanceor for any other purpose.

Continuing with FIG. 3, main housing 20 includes a base 22, an outlet 25(see FIG. 1), an outlet cover 24, a light ring 26, an outlet grille 28,a retention ring 30, and a back cover 33. An optional grip 34 is alsoshown that may be overmolded onto back cover 33 or otherwise attached tothe back cover. In the embodiment shown, grip 34 is made of silicone,but any suitable material may be used without departing from theinvention. Grip 34 provides a non-slippery surface that helps a usersecurely hold onto hair dryer 10, particularly with wet hands. Alsoattached to back cover 33 is a flexible switch cover 36. In theembodiment shown, switch cover 36 is made of a unitary piece of flexiblematerial. Alternative embodiments may include different switch covers orswitch configurations without departing from the invention. In theembodiment shown, a battery indicator 38 is located below flexibleswitch cover 36 (see FIG. 14). Of course, the battery indicator 38 maybe located at any other suitable location without departing from theinvention. Battery indicator 38 displays the level of charge of thebattery pack 16. Battery indicator 38 may display charge in any suitableway without departing from the invention. For example, in someembodiments, battery indicator 38 may change color depending on whetherthe battery is being charged or if the battery charge is low. In otherembodiments, battery indicator 38 may be comprised of multiple LED'sthat selectively illuminate depending on the level of charge.

Turning now to FIGS. 4-5, the packaging of the internal components ofbattery operated hair dryer 10 are shown. As shown, heating assembly 50is included inside top section 52. Control switches 44 and part ofbattery pack 16 are included in middle section 42. Battery managementand control module 40 is included between top section 52 and middlesection 42. Finally, part of the battery pack 16 is also included inbottom section 32.

FIG. 6 is a detail section view showing the positioning of light ring 26in relation to outlet 25 and retention ring 30. In the embodiment shown,retention ring 30 is snap fit onto outlet 25, but any suitable means ofattachment may be used without departing from the invention. Light ring26 includes a plurality of light emitting diodes (LEDs) 25 distributedaround the ring. Light ring 26 may selectively illuminate while thebattery operated hair dryer is in operation or at any other desiredtime. In some embodiments, the LEDs 25 may be able to produce a varietyof desired colors and may also be able to selectively flash or otherwiseilluminate in any desired configuration. In a preferred embodiment,light ring 26 may illuminate red when hair dryer 10 is in operation andis heating air.

Turning now to FIGS. 7-11, one embodiment of a heating assembly 50 isshown. Heating assembly 50 includes a heating element 54, a fan 56, fanhousing 58, duct 60, duct support guides 62, intake 64, and a motor 66.Heating assembly 50 is disposed within top section 52 of main housing20. In the embodiment shown, heating element 54 is a resistive heatingcoil, but any suitable heating element may be used without departingfrom the invention. Motor 66 is a brushless three-phase motor, which isa very energy efficient motor, has decreased vibration compared to othermotors, and the speed of the motor can be precisely modulated between0-100% to optimize performance and energy consumption as needed.

When air is moved through fan 56, the fan induces swirl (also calledvortices) in the air flow. The swirl does not improve the performance offan 56, but it consumes energy. It is desirable, then, to de-swirl theair after it passes through fan 56 because doing so improves theefficiency of the fan. To de-swirl the flow, a plurality of stator vanes57 are included in fan housing 58 and duct 60. Stator vanes 57 directair coming off of fan 56 and directs it toward heating element 54. Inaddition to stator vanes 57, duct 60 also includes duct support guides62, which further prevent air from swirling through duct 60. In someembodiments it may be desirable to only have stator vanes 57 withoutduct support guides 62 or vice versa. Furthermore, alternativeembodiments may do away with both the stator vanes 57 and the ductsupport guides 62 without departing from the invention.

In the embodiment shown, battery management and control module 40 ispositioned between battery pack 16 and heating assembly 50. Batterymanagement and control module 40 includes at least one microprocessor 46and a storage device 48. Battery management and control module 40includes a battery management system 68 (BMS) that balances the voltagebetween the battery cells 18 and controls the charging and dischargingof battery pack 16. In addition, BMS 68 continuously measures thevoltage of each battery cell 18. To achieve the desired balancing, BMS68 monitors the temperature of each battery cell 18 via a plurality oftemperature sensors 70 that are placed strategically throughout batterypack 16. The BMS 68 takes the temperature information provided bytemperature sensors 70 and, combined with the voltage measurements fromeach cell, determines the condition of battery pack 16 in terms of bothstate of charge and state of health. State of charge is measured as apercentage, zero to 100%, whereas state of health measures the amount ofrecoverable capacity battery pack 16 has in comparison to its beginningof life condition. It is well known in the art that the ability of abattery to maintain a charge degrades over time. BMS 68 analyzes stateof charge and state of health information before deciding how much safe,allowable current can be discharged or charged at any given time toensure that battery pack 16 stays within its degradation limits and/orexpected use life.

If the voltage varies between battery cells 18, BMS performs a balancingfunction by controlling the discharge path across any given battery cellto bleed off extra charge. By continually performing the aforementionedbalancing function, BMS 68 ensures that the battery cells 18 remainbalanced throughout the life of battery pack 16.

In addition to balancing battery cells 18 as described above, BMS 68also controls the charging and discharging of battery pack 16 so that itis done in a controlled and safe manner. Charging and dischargingbattery pack 16 and similar batteries presents numerous safety concerns.For example, uncontrolled charging of battery pack 16 may result in anover-voltage condition in one or more battery cells 18 that could resultin over-heating or fire, in extreme cases. On the opposite end of thespectrum, uncontrolled discharge of battery pack 16 is also problematic.Uncontrolled discharge of battery pack 16 may result in an under-voltagecondition that, on its own, is not dangerous. However, if a user werethen to attempt to charge an under-voltage battery cell 18, it couldresult in premature battery pack 18 degradation, over-heating, or fire.To prevent such unsafe conditions, BMS 68 continuously monitors thevoltage in battery cells 18 and includes voltage cut-offs for both overand under voltage conditions in battery cells 18 and battery pack 16.

In some embodiments of hair dryer 10, BMS 68 “knows” how much energy ispresent in battery pack 16 and can adjust and modify the heating andblowing profile of the hair dryer to ensure that the hair dryer performsoptimally given the amount of charge present in the battery pack. Ofcourse, BMS 68 may adjust the performance of hair dryer 10 in any otherdesired manner without departing from the invention.

FIGS. 12 and 13 show battery pack 16 in greater detail. In theembodiment shown, battery pack 16 is a rechargeable lithium-ion batterycomprising eight (8) individual battery cells 18. Battery pack 16 iselectrically connected to battery management and control module 40,which controls how electricity is drawn from battery pack 16 as well ashow the battery pack is charged. Of course, alternative embodiments ofbattery pack 16 may include more or less battery cells 18 in anysuitable configuration, and may also use any suitable battery typewithout departing from the invention.

Each battery cell 18 includes two terminals 19, which extend from oneend of each battery cell. In the embodiment shown, the terminals 19extend through terminal slots 72 in a terminal consolidation board 74.In the embodiment shown, terminal consolidation board 74 is a printedcircuit board, but any suitable substrate may be used without departingfrom the invention. Terminals 19 are in electrical contact with terminalslots 72, which allow for the movement of terminals 19 due to anyexpansion or contraction of battery cells 18. Terminal consolidationboard 74 electrically combines battery cells 18 into battery pack 16,which minimizes the necessary connections between battery pack 16 andBMS 68. In the embodiment shown, battery pack 16 includes two terminalconsolidation boards 74, 75, which are electrically connected to eachother. In the embodiment shown, battery pack 16 is electricallyconnected to BMS 68. Finally, battery pack 16 further includes acharging port 76, into which a user may insert a charging cable 78 tocharge the battery pack as needed. Charging port 76 may be any suitableport including, but not limited to a USB port.

In an alternative embodiment, battery pack 16 may be capable ofwireless, or inductive charging, negating the need for charging port 76.In yet another alternative embodiment, battery operated hair dryer mayinclude at least one solar cell, which would use solar energy to chargebattery pack 16. Solar charging would be particularly advantageous ifhair dryer 10 were to be used where there is no access to a chargingsource, such as a campsite. In such an alternative embodiment, it mayalso be possible to use battery pack 16 to provide power for otherdevices, such as a user's cell phone, in a manner similar to othersupplementary battery packs that are well known in the art.

In addition to balancing the charge of battery cells 18, batterymanagement and control module 40 may also optimize performance ofbattery operated hair dryer 10 in a wide variety of ways. Batterymanagement and control module 40 has the capability to control fan speedand heating output in any desirable way. Most importantly, batterymanagement and control module 40 optimizes the performance of hair dryer10 so that the user will be satisfied with the hair drying performance.In one desired drying profile, the application of heat is highest at thebeginning of the drying cycle because the hair is typically wettest atthat point. As the drying cycle continues, the heat output may reducewithout degrading performance because the hair will not be as wet andbecause decreasing the temperature will avoid damaging the hair.Additional drying profiles may be stored on storage device 48. Suchadditional drying profiles may be pre-loaded onto storage device 48, maybe “learned” by battery management and control module 40 by analyzinghow a user uses hair dryer 10, may be programmed by a user, or may becreated by any other desired means without departing from the invention.

Battery management and control module 40 is a necessary component toenable the use of batteries to power a hair dryer. As a result, thepresence of an intelligent control module opens the possibilities towhat can be done with a hair dryer. In some embodiments of batteryoperated hair dryer 10, for example, temperature sensors 80 (See FIGS. 3and 5) may be included near intake 64 and near outlet 25. Temperaturesensors 80 would measure ambient temperature in the room and be able tocompare that data to the temperature of the air exiting hair dryer 10.Depending on the difference in air temperature at intake 64 and outlet25, battery management and control module 40 can optimize the amount ofcurrent that passes through heating element 54, or can adjust the speedof fan 56 as desired.

Battery operated hair dryer 10 may include additional environmentalsensors including, but not limited to, humidity sensors, an infraredthermometer to measure hair or skin temperature, or any other desiredsensor. Furthermore, additional components may be included in hair dryer10 and connected to battery management and control module 40. Forexample, a camera could be included near the outlet 25, which wouldallow battery management and control module 40 to analyze and learn theuser's hair type, length, etc. and automatically adjust the fan speed orheat output to most efficiently dry the user's hair. Hair dryer 10 mayalso include at least one Bluetooth radio 82, wi-fi antenna 84, or othermeans to connect the hair dryer to the internet or to an internetconnected device such as a smartphone or tablet computer. Once hairdryer 10 is connected to the internet or to a smartphone, tabletcomputer, or other device, the battery management and control module 40could control the hair dryer based on any number of external factors.Taken to the extreme, hair dryer 10 could optimize performance, based ontime of day, location, local weather etc. Furthermore, if the user has aconnected device in their home such as a thermostat, hair dryer 10 couldobtain temperature and/or humidity data from the thermostat to determinethe optimal fan speed and temperature to dry the user's hair.

In some embodiments of battery operated hair dryer 10, a microphone andspeaker may be included in housing 20. The microphone and speaker may beused for any purpose including, but not limited to producing sound toactively cancel noise produced by hair dryer 10. To cancel noiseproduced by hair dryer 10, the microphone picks up noise produced by thehair dryer. Next, battery management and control module 40 creates anoise-cancelling wave that is 180° out of phase with the noise producedby the hair dryer. The noise-cancelling wave effectively cancels out thenoise of hair dryer 10, greatly improving the user experience. Inaddition to using the speaker to produce the noise-cancelling wave, thespeaker may also be used to play music or make any other desired sound.

Turning now to FIGS. 15-18, an alternative embodiment of a batteryoperated hair dryer 200 in accordance with the invention is shown.Battery operated hair dryer 200 is similar in many ways to thepreviously described embodiment, except battery operated hair dryer 200includes a heating assembly 210 that heats the air using at least onepeltier device 212 rather than a resistive heater. Peltier devices, alsoknown as thermoelectric generators, are well known in the art. Peltierdevices comprise an array of alternating n- and p-type semiconductors.The array of elements is soldered between two ceramic plates,electrically in series and thermally in parallel. When a current passesthrough one or more pairs of elements from n- to p-type, there is adecrease in temperature at the junction (the “cold side”), resulting inabsorption of heat from the environment. That heat is carries along theelements by electron transport and are released on the opposite (“hot”)side as the electrons move from a high to low energy state. Typicalsingle stage peltier devices are capable of producing temperaturedifferences between the hot and cold side of around 70 degrees Celsius(158 degrees Fahrenheit).

In the embodiment shown in FIGS. 15-18, peltier devices 212 each have ahot side 214 and a cold side 216. A plurality of heat sinks 218 arethermally connected to the peltier devices 212. Upstream from heatingassembly 210 is a motor 220 attached to a fan 221 that blows air overand through the heating assembly. Immediately downstream from heatingassembly 210, an exit duct 222 funnels heated air that has passedthrough heating assembly 210 toward and out outlet grille 28. Air thatpasses around heating assembly 210 is cooled as it passes through heatsinks 218. The cool air cannot exit hair dryer 200 through outlet grille28 because it is blocked by exit duct 222. Rather, the cooled air isdirected elsewhere, and may be directed toward battery pack 16 to aid incooling the battery pack. Of course, alternative configurations ofpeltier devices and heat sinks may be used without departing from theinvention.

What is claimed is:
 1. A hair dryer comprising: a housing; arechargeable battery pack including at least one lithium-ion batterycell, the rechargeable battery pack disposed within the housing; eachbattery cell having a discharge path, a recoverable charge capacity, anda state of charge, the state of charge measured as a percentage ofrecoverable charge capacity; a plurality of temperature sensors thatsense temperature for each battery cell; a plurality of voltage sensorsthat measure voltage for each battery cell; the battery packelectrically connected to a battery management and control module; atleast one switch to control operation of the hair dryer; a heatingassembly disposed within the housing which draws ambient air into aninlet and expels air through an outlet; the heating assembly positionedsuch that air passing through the heating assembly may be heated to atemperature greater than the ambient air temperature; the batterymanagement and control module electrically connected to the heatingassembly, wherein the battery management and control module adjusts anelectrical current delivered from the battery pack to the heatingassembly to optimize the drying performance of the hair dryer and theperformance of the battery pack; and the battery management and controlmodule capable of balancing the charge among the plurality of batterycells by controlling the discharge path across any of the battery cellsto bleed off extra charge.
 2. The hair dryer of claim 1, wherein thebattery pack includes a plurality of battery cells.
 3. The hair dryer ofclaim 1, wherein the heating assembly includes a resistive heating coil.4. The hair dryer of claim 1, wherein heating assembly includes a motorattached to at least one fan.
 5. The hair dryer of claim 4, wherein themotor is a brushless three-phase electric motor.
 6. The hair dryer ofclaim 1, wherein the heating assembly further includes a plurality ofstator vanes that straighten airflow through the heating assembly. 7.The hair dryer of claim 1, wherein the battery management and controlmodule is housed on a printed circuit board that is located within thishousing such that it separates the heating assembly from the batterypack.
 8. The hair dryer of claim 1, further including a batteryindicator that visually displays the state of charge of the batterypack.
 9. The hair dryer of claim 1, further including a light ringlocated near the outlet, wherein the light ring comprises at least oneLED.
 10. The hair dryer of claim 1, wherein the battery management andcontrol module adjusts fan speed and the amount of current supplied tothe heating element based on the temperature of the battery cells. 11.The hair dryer of claim 1, wherein the battery management and controlmodule balances the charge of the battery cells based on the temperatureof the battery cells.
 12. The hair dryer of claim 1, wherein eachbattery cell includes two terminals.
 13. The hair dryer of claim 12,wherein each terminal is electrically connected to a terminalconsolidation board.
 14. The hair dryer of claim 13, wherein the eachterminal extends through a corresponding slot on a terminalconsolidation board.
 15. The hair dryer of claim 14, wherein theterminal consolidation board is electrically connected to the batterymanagement and control module.
 16. A hair dryer comprising: a housing,the housing including an air inlet and an air outlet; a rechargeablebattery pack including at least one lithium-ion battery cell, therechargeable battery pack disposed within the housing; each battery cellhaving a discharge path, a beginning of life recoverable chargecapacity, and an in-use recoverable charge capacity, each battery cellfurther having a state of charge, the state of charge measured as apercentage of recoverable charge capacity; each battery cell furtherhaving a state of health, the state of health determined by comparingthe in-use recoverable charge capacity to the beginning of liferecoverable charge capacity; each battery cell including two terminals,each of the terminals electrically connected to a terminal consolidationboard; a plurality of temperature sensors that sense a temperature ineach battery cell; a plurality of voltage sensors that measure voltagein each battery cell; a battery management and control module having atleast one microprocessor and at least one storage device, the batterymanagement and control module electrically connected to the batterypack; the battery management and control module capable of balancing thecharge among the plurality of battery cells by controlling the dischargepath across any of the battery cells to bleed off extra charge based oninformation received from the temperature sensors and the voltagesensors; at least one switch to control operation of the hair dryer; aheating assembly disposed within the housing, the heating assemblyincluding a fan attached to a motor, and at least one heating element,wherein the motor turns the fan, which draws ambient air into the airinlet and expels air through the air outlet; the battery management andcontrol module positioned in the housing such that it separates theheating element from the battery pack; the heating element positionedsuch that air passing through the heating assembly may be heated to atemperature greater than the ambient air temperature; the batterymanagement and control module electrically connected to the at least onefan and the at least one heating element; a battery indicator thatdisplays the state of charge of the battery pack; a light ring locatednear the air outlet, the light ring comprising at least one LED; atleast one drying profile stored in the storage device; and the batterymanagement and control module capable of adjusting the electricalcurrent delivered from the battery pack to the fan and delivered to theheating element according to the drying profile to adjust the amount andtemperature of heated air expelled from the hair dryer during a dryingcycle.